// domain.js : KJ Yoo(hello@kjyoo.net)
//
// print domain name expect 'http://www'
// if you /:\/\/(www\.)?(.[^/:]+)/ -> with .com

var url = location.href;

function getDomain(url)
{
   return url.match(/:\/\/(www\.)?(.[^.:]+)/)[2];
}

document.write( getDomain(url) );